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The double burden of malnutrition in China, 1989 to 2000


Fengying Zhai and Huijun Wang, Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing, China

Introduction

Twenty-five years ago, China introduced sweeping structural reforms to the rural economy, family planning programme and financial accountability of its enterprises and service sector organizations. A rapid rise in economic productivity has resulted in continuing increases in income and changes to the traditional Chinese diet. These changes have been accompanied by shifts in the patterns of mortality and disease risk factors, and are occurring at markedly different rates across the country. A post-reform China in the new millennium faces a range of challenges in health, nutrition and family planning. Income disparities have increased as coastal areas have become wealthier, while the 300 poorest counties - most of which are in western China - suffer stagnation. The ageing of the population and increased life expectancy have contributed to an inevitable increase in the demand for long-term care.

This case study assesses trends in the Chinese dietary intake and reviews changes in nutritional status, morbidity and mortality.

Demographic and health indicators

Over the past three decades, the Chinese population has expanded from 987 million to 1.267 billion (Table 1). There has also been an increasing trend towards urbanization, with the urban proportion of the population growing from 19 to 36 percent. Birth and death rates have been declining, while the natural growth rate has remained relatively stable (Figure 1). Additional demographic and development indicators are presented in Table 2. The declining birth and death rates of the past 20 years are causing the Chinese population to become older, with a decreased percentage in the 0 to 14 years age group and increases in the percentages of adults (15 to 64 years) and elderly (65 years and more). Population health indicators have improved over the past 30 years, and 90 percent of Chinese adults are literate. Although the proportion of population with access to safe sanitation has increased, it remains low, at less than 50 percent (State Statistical Bureau, 2002).

TABLE 1
Trends in population by residence and gender, 1980 to 2000

Year

Total population, millions (at year-end)

By sex

By residence



Male (%)

Female (%)

Urban (%)

Rural (%)

1980

987

51.45

48.55

19.39

80.61

1985

1 058

51.70

48.30

23.71

76.29

1990

1 143

51.52

48.48

26.41

73.59

1995

1 211

51.03

48.97

29.04

70.96

2000

1 267

51.63

48.37

36.22

63.78

Data include military personnel of the Chinese People’s Liberation Army, but not the populations of Hong Kong, Macao and Taiwan.

Source: State Statistical Bureau, 1980 to 2002.

FIGURE 1
Trends in birth, death and natural growth rates in China, 1980 to 2000

Source: State Statistical Bureau, 1980 to 2002.

TABLE 2
Trends in population structure and selected health and education indicators, 1980 to 2000

Indicator

Year

Source


1980

1990

2000


Population 0-14 years (%)

35.5

27.7

22.9

UNESCAP, 2004

Population 15-64 years (%)

59.8

66.9

70.2

UNESCAP, 2004

Population ³ 65 years (%)

4.7

5.4

7.0

UNESCAP, 2004

Annual population growth rate (%)

1.2

1.4

0.8

UNESCAP, 2004

Infant mortality rate (per 1 000 live births)

41

33

28

UNESCAP, 2004

Overall life expectancy (years)

67.8 (1981)

68.6

71.4

Chinese population census

Female life expectancy (years)

69.3 (1981)

70.5

73.3

Chinese population census

Male life expectancy (years)

66.4 (1981)

66.9

69.6

Chinese population census

Adult literacy (%)


78.3

90.9 (2002)

UNDP, 2004

Population with access to improved sanitation (%)


29

40

UNDP, 2004

Population with access to an improved water source (%)


71

75

UNDP, 2004

Employment and economy

The Chinese economy has experienced exponential growth in the past decade, with per capita gross domestic product (GDP) rising from 460 yuan in 1980 to 7 084 yuan in 2000 (Figure 2). Since 1990, per capita GDP has grown by an average of 8.6 percent per year (UNDP, 2004). Although the number of employed people has been rising in the past decade, the number and percentage of unemployed people indicate a need for increased focus on job creation (Table 3) (State Statistical Bureau, 2002).

FIGURE 2
Trends in per capita GDP (yuan), 1980 to 2002

Source: State Statistical Bureau, 1980 to 2002.

TABLE 3
Trends in unemployment in China, 1991 to 2001

Indicator

1991

1995

2000

2001

Total number of employed people (10 000s)

58 360

67 947

72 085

73 025

Number of registered unemployed people in urban areas (10 000s)

288

520

595

681

Registered unemployment rate in urban areas (%)

2.3

2.9

3.1

3.6

Source: State Statistical Bureau, 1990 to 2002.

Data sources for dietary intake, nutrition and health indicators

Three main data sources were used to analyse the trends in diet, nutritional status and disease burden in the Chinese population. The primary source of data on dietary intake is the China Economic, Population, Nutrition and Health Survey (CHNS), which was conducted in 1989, 1991, 1993, 1997 and 2000. The National Nutrition Survey (NNS) was conducted in 1992 and 2002 - this report uses only the data on chronic disease risk factors from NNS. The third data source is the China Disease Surveillance System. An outline of each of these sources is given in the following subsections

China Economic, Population, Nutrition and Health Survey

CHNS covers nine provinces that vary substantially in geography, economic development, public resources and health indicators (Figure 3). It is not nationally representative however. A multistage, random cluster sample is used to draw the sample surveyed in each of the provinces. Counties in the nine provinces are stratified by income (low, middle and high) and a weighted sampling scheme is used to select four counties randomly in each province. The provincial capital and lower-income cities are selected when feasible. Villages and townships in the counties and urban and suburban neighbourhoods in the cities are selected randomly. From 1989 to 1993, there were 190 primary sampling units; a new province (and its sampling units) was added in 1997, and currently there are about 3 800 households in the overall survey, representing 16 000 individuals of all age groups. The data can be stratified by region, gender and province. Follow-up levels are high, but families that migrate from one community to another have not been followed.

CHNS collects information on all the individuals living in a household. A complete household roster is used as a reference for subsequent blocks of questions on time allocation at home (e.g., child care, elderly care and other key home activities) and on economic activities. Questions concerning income and time allocation aim to take into account all the activities that each person could have engaged in during the past year, both in and out of the formal market. Information on water sources, construction and housing conditions and ownership of consumer durables is gathered from respondents. Three days of detailed food consumption information is collected by combining household- and individual-level data. Household food consumption is determined by a detailed examination of changes in inventory between the start and end of each day for three consecutive days, in combination with a weighing technique. Dietary intake at the individual level is surveyed by 24-hour recalls for the same three consecutive days by asking individuals to report all their food consumption for each day, both away from and at home.

Recent CHNS have used food composition tables from 1992 to determine the nutrients consumed. In addition, individual dietary intake is collected for each household member for three consecutive days, irrespective of age or relationship to the household head. Adults and children receive detailed physical examinations that include weight, height, arm and head circumference, mid-arm skin fold and blood pressure (adults only) measurements. Limited clinical nutrition and physical functioning data were collected in 1993, 1997 and 2000. In 1997, the survey added daily living activities, related information for older adults and a new set of physical activity and inactivity data for all respondents.

FIGURE 3
Map of the CHNS survey regions1

1 Light shaded regions included in CHNS

National Nutrition Survey (NNS) of China

The third NNS of China was conducted in 1992 and the fourth in 2002. In 1992, a stratified multi-stage cluster random sampling method was used. The survey covered the residents of sample units selected from 30 provinces. The sample size was 32 sites, including 960 households for each province, metropolis and autonomous region. Adjustments were made in some provinces to provide a total sample of 28 000 households in 30 provinces.

The fourth NNS of 2002 was China’s first comprehensive nutrition and health survey. It systematically integrated several previous, separately organized surveys on nutrition, hypertension, diabetes, etc. into one survey and included some new indicators related to social and economic development. Cities were classified as large, medium or small according to their level of economic development. Beijing, Shanghai, Tianjin and Chongqing were included in the total of 18 large cities. Rural areas were classified as first, second, third or fourth class, based on economic level and population size. First class rural areas were the richest, and fourth class the poorest.

A stratified multi-stage cluster random sampling method was adopted to sample 71 971 households (24 034 urban and 47 937 rural) chosen from 132 counties in the 31 provinces, autonomous regions and municipalities directly under the central Government of China. The data can be stratified by urban and rural residence, gender and age. The survey covered diet, nutrition and a range of diet-related non-communicable disease (DR-NCD) risk factors, including hypertension, diabetes, obesity and abnormal blood lipid levels.

China Disease Surveillance System

The China Disease Surveillance System was established in 1989. A multistage, randomized cluster process was used to draw the sample. The first layer was based on geographic representation, the second on urban and rural areas, and the third on economic and development levels and demographics. Cities were classified as large, medium and small. Rural areas were classified into four classes according to socio-economic status, population and the index of death, which were obtained from the Chinese population census of 1982. The four classes were (a) the richest rural areas, (b) the richer rural areas, (c) the poor rural areas, and (d) the poorest rural areas.

The survey covered 10 million people, about 1 percent of China’s population. In 1989, 9 261 436 people were chosen for the sample, 2 253 963 from the cities and 7 007 473 from rural areas. A survey was conducted on this sample every year to collect data on demographics, births and deaths, infectious disease, smoking and other lifestyle factors. This report uses data from the period 1990 to 2002 to describe trends in the burden of disease.

Trends in dietary intake

This case study uses data from NNS and CHNS to identify trends in the food consumption of the Chinese population. In the period 1989 to 2000, total dietary energy intake decreased for all age groups - in adults 20 to 59 years of age by 39 kcal per day. However, the percentage of dietary energy derived from fat increased for all age groups, reaching 30.9 percent in people aged 60 years and over and 29.8 percent in children under nine years.

FIGURE 4
Total energy intake and dietary energy from fat in China, 1989 to 2000

Trends in the intakes of children aged two to five years

Over the past ten years, children’s intakes of cereals and tubers declined from 240 to 205 g and from 64 to 40 g per day, respectively (Figure 5). The intake of vegetables remained relatively stable, while fruit intake decreased from 33 to 17 g per day. During the same period, the consumption of animal food increased - meat by 80 percent, and eggs by 75 percent (Figure 6). From 1997 to 2000, the consumption of milk increased from 10 to 15 g, which may signal an increasing trend in dairy consumption. Total energy intake decreased slightly, but the diet became proportionately richer in fat, which rose from providing 22 percent of dietary energy in 1989 to 31 percent in 2000 (Table 4). These trends generally represent positive developments in children’s diets, indicating greater dietary variety, intake of high-quality protein sources and increases in essential micronutrients, including calcium, iron and zinc. However, in addition to the rapidly escalating percentage of dietary energy derived from fat, two other alarming trends are decreasing intakes of vitamins A and C, most likely resulting from decreased intake of fruits, which are good sources of these nutrients.

FIGURE 5
Trends in per capita intakes of vegetable products among children aged two to five years, 1989 to 2000

Sample sizes: 1989, 1 009; 1991, 1 086; 1993, 982; 1997, 514; 2000, 437.
Source: CHNS.

FIGURE 6
Trends in per capita intakes of animal products among children aged two to five years, 1989 to 2000

Sample sizes: 1989, 1 009; 1991, 1 086; 1993, 982; 1997, 514; 2000, 437.
Source: CHNS.

TABLE 4
Trends in intakes of nutrients in children aged two to five years, 1989 to 2000

Year

Nutrients


Energy (kcal)

Protein (g)

Fat (g)

Calcium (mg)

Iron (mg)

Zinc (mg)

Vitamin A(ug)

Vitamin B1(mg)

Vitamin B2(mg)

Vitamin C(mg)

1989

1 240

36.8

30.1

212.5

11.2

5.7

304.9

0.6

0.4

56.5

1991

1 363

41.6

37.1

215.5

12.8

6.3

286.5

0.7

0.5

47.0

1993

1 264

39.4

32.5

209.8

11.7

6.1

268.8

0.6

0.4

52.3

1997

1 179

36.1

37.5

220.4

11.8

5.9

243.3

0.5

0.4

39.8

2000

1 225

38.3

42.8

246.3

13.2

6.3

298.7

0.6

0.5

44.9

Sample sizes: 1989, 1 009; 1991, 1 086; 1993, 982; 1997, 514; 2000, 437.
Source: CHNS.

Trends in the dietary intake of adults

The shift in the Chinese diet follows a classic pattern of Westernization. Economic progress, linked in part to the liberalization of food production controls and the introduction of a free market for food and food products, is connected to these important shifts in diet. Both the NNS and CHNS data show that intakes of cereals and tubers have decreased considerably during the past two decades, in both urban and rural areas and among all income groups. The results are shown in Tables 5 and 6 and Figure 8. The total intake of vegetables decreased and the intake of fruits remained stable over these years. At the same time, the daily intake of animal foods showed a large increase, with pork and eggs increasing far more rapidly than the others. Urban residents’ per capita daily intake of animal foods was higher than rural residents’ (Table 5). The intake level of animal foods for the high-income group was almost twice that for the low-income group (Figure 9).

Over the past decade, the proportion of dietary energy derived from fat in the adult diet increased dramatically from 19 to 28 percent, mainly owing to the replacement of dietary energy from carbohydrates (Figure 7). The food group changes that accompanied this trend in increasing fat intake included an increased consumption of meat, especially pork, poultry and milk. Surprisingly, the consumption of animal fats and vegetables oils did not increase, in either urban or rural areas (Table 5). However, about one-half of dietary fat came from edible oil, while the consumption of refined animal fat decreased. The pace of this trend is alarming and signals a need to slow the population’s intake of fats, which will soon exceed recommended levels. Decreasing consumption of vegetable oil, pork and pork products is critical in controlling the fat intake in the Chinese diet.

An analysis of current trends in intakes of the major food groups, stratified by income and urban/rural residence, provides some interesting insights. Certain trends in intake (e.g., increased fruit, vegetables and milk) seem to be dominated by residence location, with urban consumers more likely to have increased intakes of fruit and milk, and rural consumers more likely to consume more vegetables. Income can be seen as driving the intake of sugar, while a combination of residence location and income seems to be significant in meat consumption trends.

FIGURE 7
Trends in shares of macronutrients in total dietary energy intake, 1989 to 2000

TABLE 5
Trends in intakes (g/day) of food groups among adults (18 to 45 years) by residence, 1989 to 2000

Food

Total

Rural

Urban

1989

1991

1993

1997

2000

1989

1991

1993

1997

2000

1989

1991

1993

1997

2000

Cereals
















Rice

348

337

320

297

274

362

338

335

312

290

316

336

284

262

237

Wheat

190

196

199

181

152

193

196

211

193

154

183

194

169

153

146

Maize

44

25

21

20

14

60

28

27

25

16

10

18

6

6

7

Other

19

10

11

8

6

26

9

12

9

6

5

11

6

6

7

Tubers
















Potato

18

26

23

28

27

22

28

27

32

30

9

23

12

19

19

Sweet potato

58

24

13

10

6

75

26

16

13

7

21

18

6

4

3

Other

71

44

53

45

40

77

41

55

46

41

58

50

48

44

48

Meat
















Beef

3

4

6

7

7

2

4

5

5

5

5

5

10

11

11

Pork

52

59

62

60

69

44

59

52

49

60

71

59

89

86

91

Poultry

7

7

9

12

14

4

7

6

10

12

12

7

14

17

19

Eggs

11

14

15

24

26

9

13

12

20

23

16

15

22

33

32

Other

2

1

1

2

2

2

1

1

1

1

2

1

2

5

4

Fish

24

21

22

28

26

22

21

20

25

25

27

22

28

35

30

Dairy
















Fresh milk

1.2

1.8

2.1

1.5

3.8

0.1

1.3

0.8

0.5

1.7

3.5

2.9

5.3

3.9

9.3

Powdered milk

0.1

0.2

0.1

0.3

0.3

0.1

0.2

0.1

0.1

0.0

0.3

0.3

0.2

0.8

0.8

Legumes
















Pulses

79

80

77

81

96

78

80

77

79

96

80

80

78

87

95

Nuts

3

3

2

2

4

3

3

2

3

4

5

3

3

2

3

Vegetables
















Green leafy

227

181

178

172

159

242

181

188

183

169

182

151

148

133

163

Vegetables

53

84

94

98

98

53

86

102

98

100

53

79

76

97

92

Other

16

13

12

10

8

19

16

13

11

8

8

8

10

9

7

Fruit
















Citrus

2

1

1

2

1

1

1

1

1

1

3

2

2

3

2

Other

12

8

11

8

11

13

7

10

5

7

11

10

14

17

20

Fats and oils
















Animal fat

18

13

10

10

12

19

14

11

10

12

15

12

9

9

12

Vegetable oil

32

22

22

31

30

30

22

21

30

30

37

22

26

34

30

Sugar
















Soft drinks

0.1

0.1

0.1

0.4

0.3

0.1

0.1

0.1

0.1

0.2

0.1

0.1

0.2

1.1

0.4

Confectionary

2.6

1.8

2.0

2.5

2.0

2.3

1.8

1.4

2.3

1.9

3.5

1.8

3.3

3.0

2.3

Other foods

54.1

32.8

31.4

38.5

39.8

51.1

33.6

31.0

38.3

40.1

60.8

31.2

32.2

39.0

38.8

Sample sizes: 1989, 5 789; 1991, 5 838; 1993, 5 468; 1997, 5 334; 2000, 4 831.
Source: CHNS.

TABLE 6
Food consumption in rural and urban areas of China (g/day), 1992 and 2002

Foods

Total

Rural

Urban

1992

2002

1992

2002

1992

2002

Rice

226.7

238.3

255.8

246.2

223.1

217.8

Wheat

178.7

140.2

189.1

143.5

165.3

131.9

Other cereals

34.5

23.6

40.9

26.4

17.0

16.3

Tubers

86.6

49.1

108.0

55.7

46.0

31.9

Green leafy vegetables

102.0

90.8

107.1

91.8

98.1

88.1

Other vegetables

208.3

185.4

199.6

193.8

221.2

163.8

Fruit

49.2

45.0

32.0

35.6

80.1

69.4

Nuts

3.1

3.8

3.0

3.2

3.4

5.4

Meat

58.9

78.6

37.6

68.7

100.5

104.5

Eggs

16.0

23.7

8.8

20.0

29.4

33.2

Fish

27.5

29.6

19.2

23.7

44.2

44.9

Dairy

14.9

26.5

3.8

11.4

36.1

65.8

Vegetable oil

22.4

32.9

17.1

30.1

32.4

40.2

Animal fat

7.1

8.7

8.5

10.6

4.5

3.8

Sugar and starch

4.7

4.4

3.0

4.1

7.7

5.2

Salt

13.9

12.0

13.9

12.4

13.3

10.9

Sauce

12.6

8.9

10.6

8.2

15.9

10.6

Source: NNS.

FIGURE 8
Trends in cereal consumption in adults (18 to 45 years) by income group and residence, 1989 to 2000

Sample sizes: 1989, 5 789; 1991, 5 838; 1993, 5 468; 1997, 5 334; 2000, 4 831.
Source: CHNS.

FIGURE 9
Trends in consumption of meat in adults (18 to 45 years) by income group and residence, 1989 to 2000

Sample sizes: 1989, 5 789; 1991, 5 838; 1993, 5 468; 1997, 5 334; 2000, 4 831
Source: CHNS.

Trends in the achievement of various population nutrient intake goals are shown in Table 7. The percentage of dietary energy derived from fat increased in all age groups. The dietary fat intake in suburban and town areas increased rapidly. The proportion of energy from fat reached 30 percent in suburban and town areas, and 35 percent in urban ones. The percentage of people consuming at least 400 g of fruits and vegetables a day dropped for all age groups, while those consuming less than 5 g of sodium chloride also decreased. In 1997, urban adults’ intake of cholesterol reached 361.6 mg/d, exceeding the recommended daily allowance (RDA) of 300 mg/d. The cholesterol intake of 54 percent of urban adults was more than 300 mg/d. The cholesterol intakes of suburban and town residents increased to 250 mg/d and 270 mg/d, respectively, but that of rural residents remained stable at a lower level of 150 mg/d. High intakes of dietary fat, sodium and cholesterol increase the risk of chronic diseases such as obesity, diabetes, cardiovascular disease (CVD) and some cancers, especially in middle-aged and elderly populations.

TABLE 7
Achievement of population nutrition intake goals

Age (yrs)

Year

% energy intake from fat

55-75% energy intake from carbohydrate (%)

< 5 g sodium chloride per day (%)

< 10 % energy intake from sugars (%)

³ 400 g/day fruit and vegetables



< 15

15-30

> 30





10-19

1989

43.0

35.5

21.5

52.7

37.0

100.0

23.1


1993

34.8

45.4

19.8

57.1

22.5

99.9

23.1


2000

12.3

45.7

42.0

57.1

18.6

97.7

15.3

20-59

1989

28.1

43.9

28.0

56.3

27.9

99.6

29.3


1993

28.3

47.9

23.8

57.6

17.0

99.9

26.0


2000

11.3

44.3

44.4

54.8

13.9

97.8

21.3

³ 60

1991

29.4

51.1

19.5

60.8

16.6

99.8

18.8


1993

23.3

47.1

29.6

58.1

22.7

99.7

16.2


2000

9.2

37.7

53.1

46.9

14.6

98.4

15.4


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